Snow pack will get worse before it gets better

Warming trend will trigger more slides, but may help in long run

The word from the Canadian Avalanche Centre (CAC) is that
avalanche conditions will actually get worse in the South Coast before they get
better, but don’t write off the entire season just yet.

“What’s happening now is we’re in an extended warming period,
and in the short term it’s going to cause more pain in the snowpack,” said Ilya
Storm, an avalanche forecaster for the CAC in Revelstoke. “It’s going to
increase the avalanche hazard.”

Storm explained that ice and hard snow form strong bonds, “but
as you warm up the snow loses strength,” he said. “You can do things with snow
or cold ice that you can’t do with a lake. As the snow warms, it causes the
snow to creep, glide and deform more, and there’s more stress on these deep,
weak layers we’ve been talking about.”

After a prolonged freezing period in December, the entire
province was hit with storms of really dry, light, and powdery snow. Heavier
snow followed, compressing that lower layer but not bonding with it. As a
result, there is nothing to anchor all the recent snow to the slopes.

The upside is that the warming will trigger many natural
avalanches, and could cause the weak layer to bond.

“We have a couple of ideas how it will play out, and in the
long term the warming may — and I emphasize ‘may’ — help
us,” said Storm. “It will help the snow to settle, and when it turns cold again
it will strengthen. That could — and again I emphasize ‘could’
— help us in the long term.

“That’s the big question, and we won’t know the answer until we
see how everything plays out, and whether it’s enough to help the deep weak
layers.”

The other thing that could help stabilize slopes, “is 40 days
and 40 nights of snow,” Storm adds. “A whole bunch of snow, followed by another
cycle or two of big, amazing avalanches, should squish all this weak stuff
together… until it’s one big coastal snowpack again.”

Storm says the current type of “upside down” snowpack is more
common in the Rockies than the coast and interior of the province.

Rain could help, he said, by triggering natural avalanches
quickly, but otherwise could create more problems by creating a crust layer
that could be as dangerous as the dust layer, says Storm. Last winter, 2007-08,
the instability that lasted most of the season was the result of rain earlier
in the year.

“Rain on the mountain top is not like hitting the restart
button,” he said. “It’s a double edged sword, on one side it could be good and
possibly help the snowpack, on the other it could make things worse.”